oil, and wine — so that only the largest cities had to import food from any distance. There were not enough of these cities to support a flourishing grain trade, and in any case Rome and Constantinople drew their food supplies largely from the imperial estates of North Africa and Egypt. Trade in manufactured articles could not take the place of trade in food because the Romans, with abundant slave labor, never took much interest in efficient production. They used few machines; they clung to cumbersome methods of production, and in these circumstances no one manufacturing center could have any great advantages over other districts. Except for luxury articles, each province of the Empire was relatively self-sufficient, and even within the provinces rural districts drew little from the towns. Any great estate produced most of the food needed by its inhabitants, and the artisans who lived there could make all the furniture, pottery, tools, and clothing which were required. In short, the Empire was never really an economic unit, and the lack of common economic interests made disintegration easier.
Political autocracy and economic stagnation weakened loyalty to the emperor and to the Empire. The rulers of imperial Rome had tried hard enough to build up loyalty with their temples devoted to the imperial cult, their monuments and public buildings, their ceremonies and festivals. Their efforts failed partly because the cult of emperor-worship and Rome-worship was synthetic, foisted on the people from above instead of springing spontaneously from popular beliefs and experiences — even more because the average inhabitant of the Roman Empire could take no interest in the affairs of an organization in which he played no significant role. At the very end of the Empire the emperors tried to use religious belief to take the place of the civic loyalty which was missing. They accepted Christianity as the religion of the state and hoped that devotion to the new religion would inspire devotion to the protectors and upholders of the faith. This attempt also failed, except in the East. Throughout most of the Empire, Christian leaders were unwilling to bind themselves too closely to the political fortunes of